Boiler feed control



May 26, 1942. J. A. CAMPBELL BOILER FEED CONTROL Filed Jan. 10, 1940 2 Sheets-Sheet l Y .Jpn n/ar Jan/Ii hnpztu WE Q y 1942 J. A. CAMPBELL 2,284,130

BOILER FEED CONTROL Filed Jan. 10, 1940 2 Sheets-Sheet 2 vo o @J JZJ P/Y/an Jam/v19. (kn/earl:

Patented May 26, 1 942 .boilers in general.

2,284,130 BOILER FnEn coNTRoL 7 Julian A. Campbell, Long Beach, Calif. Application January 10, 1940, Serial No. 313,234 Claims. I c1.12 2e 451.1)

This invention has to do generally with apparatus for controlling the level of heated liquid in a chamber by regulation of the liquid feed thereto in accordance with changes in the liquid level, and is concerned particularly with an imsmall rise of the water level will run the water a much-longer distance along the tube. For example, in some instances, aone inch water rise may run the water 12 inches along the tube.

proved feed water control for steam boilers, de-

signed to be less afiected than ordinary regulators of this type by abnormal conditions such as sudden and wide variations 'in the boiler Water level, and to be capable of maintaining a more constant water level under normal conditions. V

The invention maybe further characterized as pertaining to improvements in regulators of the type disclosed in my copending application Serial Number 220,719, filed July 22, 1 938,-now Patent The resultant cooling of the tube may be sufiicientto entirely orpartially close the feed water valve, and with thecoolingeffect of the feed water entering the boiler entirely or greatly cut ofi, both the-liberation of steam and consequent expansion of the boiler water are much greater. The resulting high water level is of course conducive to wet steam and unnecessarily high fuel,

7 consumption. Only a relatively short'period of time is required to elevatethe drill pipestring,

the length of one pipestand, i, e. the length of 7 section to be disconnectedin each successive Number 2,207,214 on Boiler feed water control, 1

and comprising as the principal control element an incined and longitudinally expansible metal tube connected at'its upper and lower ends to the steam and water spaces, respectively,- of the boiler so that the water stands in the tube at a level intermediate its ends and corresponding substantially to the water level in the boiler. As

that level varies, the tube longitudinally expands or contracts and operates the boiler feed water control valve through suitable connections therewith. As will be understood, the present type of regulator is adaptable for water level control of satisfactory for the control of feed" water to oil field boilers, and may be described typically by reference thereto since the boilers'used in drilling a well present some of the most diflicult con ditions to be encountered in liquid level control.

In well drilling operations, whenelevating the pipe string from the hole the steam powered draw-works is run at practically full speed and the resultant rapid draw-ofi of steam from the boiler drops the pressure, which in turn causes It has proven particularly operation. While each stand of pipeis being unscrewed and landed on the derrick floor or a hanger, and while the elevator is being lowered to engage the next pipe stand, practically no steam is required, the boiler fires are low and the water settles back and runs down the controller tube, only to surge up again when the pipe string is again elevated. This repeated surging of water in the controller tube, tends to cause the water to be excessively heated due to the fact that heat is supplied to the tube by the surging water faster than radiation can cool the tube, and consequently the feed control valve will open more than is desirable, and an excessively high Water level will occur in the boiler.

One'of the primary objects of the invention is to cool the controller tube, preferably automatically in accordance with the rise and fall of the boilerwater level, so that the tube is given av delayedsensitivity rendering its operationlless affected :byrelatively rapid surges of the Water,

the usual automatic fuel control to more ining released into the Water from the heating surand at the same time impart to the tube greater sensitivity under normal operating conditions. In its preferred form, the invention contemplates cooling the tube and controlling the degree of cooling automatically by the rise and fall of thelboiler water level, so that a falling level reduces the cooling and a rising level increases it.

faces below the water level. This expansion of I the Water may be observed by the rise of the water level in the gauge glass. This condition is momentary, however,'because the rapid generation and release of steam soon builds up the pressure, causing the firing to be reduced and the water level in the boiler to lower.- Elevation of the boiler water level is accompanied'bya rise of water in the inclined regulator tube, and by reason of the tube being inclined, a relatively Generally speaking, these objective are accomplished by applying a cooling fluid, preferably boiler. feed water, to an upper portion of the controller tube above the normal Water level therein,

and regulating the rate at which the cooling fluid is applied to thetubein accordance with movements of the feed water. valve, and there- 'fore in accordance with changes in the boiler v water level. u

Preferably a constantly flowing stream'of cooling water is applied tothe controller tube, and

the flow of this stream is regulated to produce ,in-

- regulator l6 may be described generally as comcreased heating or cooling of the tube, as may be required in accordance with variations in and the resultant heating of the tube causes the feed valve to open, the cooling water flow to the a the boiler water level. When through increased firingthe. water level'drops in the controller tube tube is reduced so that the tube is permitted to heat sufliciently to slightly openthe feed valve, allin a manner such that. the water is raised to its proper level and-a balance is established in the operation of the tube, feed water and cooling water control, to maintain that level. Sudden or spontaneous responsiveness of the regulator to surging of the boiler water, and the resultant difficulties ordinarily encountered; areobviatedi in that the tube has delayed. action and its re sponsiveness is stabilized. This delayed action results from maintaining in contact with ...the I tube a stream of cooling; water thatin effectinprising apair-of elongated convergent members Hand l5 interconnected'at. their outer ends by acastin'g IE or othersuitable means, and pivotally mounted at their divergent ends on a stationary support; l'l. Member l5 comprises an inclined tube made of suitable material, such as brass or for" some purposes a proper grade and quality; of steel, having a predetermined coefficient of expansion. The lower end of the tube is connected with the water chamber of the boiler by pipe I8 extending to the forward end [3a of the boiler and connecting into the lower end of the. gauge glass I9 having the usual valved "connections 2| and 28 with the boiler chamber above and belowthe normal liquid level L. Tube I5'is positioned. at an elevation such that norcreases. thetotal, specific heat of the tube and 7 thereby introduces a time element in changing the temperature of thetube and; causing the tube to, influence the feed water. ,con t p jvalvez; This t ma b e heri d y u ne ni ex r heavytube; sayxof'redibrass or in some instances ,stainlesssteel, which prornotes'jdelayed action through; retarding thehe'at transmission. Asa

r s l 1 th s effects, "th e m ratur changesof thetubeis extended: over a suflicient lengthof time-to overcome the effector water;

surge, and yet under all normal conditions, the control-ler has extreme sensitivity that willfpre- I V ventany appreciablechange;in-the' water level.

.'I he various objects and; features of the in mally the boiler water stands in the tube at a level"L located substantially at. the longitudinal centerof the tube.

4 Thetube 1-5 is pivotally connected to; the support l] by a casting 22 attached to the web Ha of: the supportbybolt 23. Member l4 may be of janysuitable form, and is shown typically as comprising a' solidforked steel'rod pivotally attachedat 24 to the support H by a yoke hav vention discussed in the foregoing, as well as additional details; will be better understood from thefollowingdescription of the invention as emrbodied in certain typical andil-lustrative forms. Throughout the description reference is had to Fig. 4 is' a'view illustrating a variational means for applying a cooling fluid to the upper portion of the inclinedregulator tube; and w Fig. .5 isa .view similar to Fig. 4 illustrating a further variational form.

he regulator assembly generally indicates. at

ingan" adjustable connection at 2'6 with the rod in order to permitvariation" of the effective length of thefrod with relation to the tube I5. The elevation of members [4 and i5 is variable by providing thesupporting web lid with a vertical series of spaced'holes 21 into which bolts 23 and 24 may be inserted. 'The outer end of tube l5'isi threaded at 28into the hollow casting Hi, to the sides of which the forked branches a and Mb of member are pivotally connected as at 29." r

r The casting l6 and the upper portion of tube l5 above the water level therein communicate with the steam chamber of the boiler by a pipe or flexible conduit 30, such as copper tubing, connected at 3| with the upper gauge glass fitting "3 2, which in tuiri is connected by pipe 20 with the boiler steam chamber.

Thus with tube l5 communicating at its lower end with the water space in the boiler through pipe l8, and at its upper end with the boiler steam chamber through pipe 30, the level at which the water stands in the tube'will normally correspond with the water level L' in the boiler, and during normal or relatively slow changes in the boiler water level, the

two levels will vary 7 correspondingly and almost simultaneously. A-suitable signaling device may it] l, is shown to be connected'to and. to j Y Jploy a-signaling system, generally indicated at control valve. I [in the feed water supply line"l2 leading to the .boiler, the wall of which isconventionally indicated at.pl:3 Aswill be under stocd the show ng of the boiler .is merely conventional since the regulator is adaptable for con- 'trollingfthe water level in boilersof various types and-designs. For the. purpose 'of explaining the be employed inassociation with the regulator to Iter levels in the boiler.- For example, I may emindicat'e ab'normallyhigh or dangerously low wa- 33,,comprising a steam whistle 34' operatively connected through a linkage generally indicated at 35 with lug I611. on casting 16, so as to blow when predetermined high and low water levels invention it will sufiice to: refer to the regulator HI as being .so, positioned-with relation to the normal water, level L ofthe boiler as to enable I the regulator to operatethe valve H in response toyariationsin the water level, all as will be fully expiainedhereinaften. While the inventionis api plicable to various typeof regulators embodying anin cline'd tube within which the water stands of the tube, I have shown for the purpose. of exat a level intermediate the upper and lower ends occur. The signaling device comprises no part ofthe present invention, and further details concerriingit may be-had from my copending application referred to above.

Being connected with the steam chamber, the upper portion of tube l5 above the liquid level therein is heated toa higher temperature than the lower; portion of the tube, since the latter is cooled below the boiler water temperature due to v heat radiation from the tube. It-follows that as the water level rises or falls, the tube longitudinally contractsor expands by reason of the fexposure of a lesser length of the tube to the steam temperature and a greater length to the treated for the removal of any corrosion and water temperature when the'water level rises,

or conversely when 'the water level drops; The

length of rod I4 remaining fixed, longitudinal contraction orexpan sion of the tube I 5 produces of the tube, length of the members, andtheir angularity. The casting I6 is operativelyconnected to the feed water control valve-II by an adjustable length push rod 36 attached at its upper end to the casting lug 31 and at its lower end to the valve operating lever 38.

Assuming the boiler water level to rise above normal, the accompanying rise of the water level L in tube I5 causes the latter to'contract longitudinally, and the resulting downward deflection of the interconnected end of the members depresses rod 35 to close the valve II and restrict the feed supply until the boiler water level drops to normal. Conversely, when the boiler water level falls below normal, the exposure of an increasing length of the tube I5 to the steam tem perature causes the tube to expand and rod 35 to be moved upwardly to open the valve II' and increase the rate of feed water supply.

Further as regards the expansible tube I5, it may be desirable to increase the normal temperature difierential between the upper and lower portions of the tube exposed to steam and scale forming compounds. The filter. periodically may be cleansed and freed of clogging'bodies simply byclosing valve 63, opening valve 64 in the blow-ofi line 65, and reversing the flow.

through line GI and the filter 62.

water, respectively, and ultimately to increase the responsiveness or sensitivity of the tube to relatively small changes in the water level. This object is accomplished by abnormally increasing heat radiation from the water-containing portion of the tube, as by providing the latter with a series of annular fins 39 extending from the casting 22 at least a substantial length of the tube below the normal water level. larly formed fins 39 affiord greatly increased heat radiating surface area, and permit free expansion or contraction of the finned portion of the tube without interference by or distortion of the fins.

The feed water control valve Il may of course be of any suitable form, and is shown typically as comprising a body 40 having an inlet 4|, an outlet 42 and a valve 43 movable vertically with relation to its seat 44 by stem 45. Leakage from the valve body along the stem isprevented by a tubular sleeve 56 of rubber or other similar material, clamped at its upper end between the interior shoulder 46 of bushing 41 and the lower wedge-shaped end of an insert 48 that is pressed against the tube by tightening nut 49. The lower end of sleeve 50-has a fluid-tight connection with the stem 45 by way of a hollow nut 5I threaded at 52 on the stem and pressing the sleeve against a wedge-shaped annulus 53 carried by the stem. The stem is pivotally attached at 54 to lever 38 which in turn is mounted on the valve body by link 55 and. bracket 56.

Provision is made for controllably applying cooling liquid to the upper portion of the regu lator tube I5 through a flexible pipe, such as copper tubing 51, connecting at 58 into one side of the casting I5, as illustrated in Fig. 3. Preferably the cooling fluid used is boiler feed water taken from the supply line at the inlet side of the valve 43, as by way of line 59 tapped at'BIl into the lower portion of the valve body. The cooling water flows from line 59 to line 6I"containing a suitable filter 62 within which the water is freed of any solids, andif desired, chemically The annu The'supply of water through line GI and pipe 51 t'o'the upper end of tube I5 preferably is rendered controllably variable in accordance with the operation of the feed water control valve II, and therefore in accordance with variations of the water level in the boiler, by a' suitable valve device 66 in line BI and operated by'a connection with the valve stem '45. The device 66 typically may comprise a tubular body 61 having a threaded neck 68 supported on the bracket 69, and containing a slide valve I0 having a downwardly extending stem 1I' attached to stem- V 45 by the adjustable connection I2. Leakage of water from the valve body about stem II is prevented by a flexible rubber sleeve 13 maintained in spaced relation to the stem by the coil spring I4, and having its upper end fitted about an enlargement I5 and held in place by a wire I6. The lower end of sleeve I3 is pressed against the internal body flange 11 by a Wedge sleeve I8 held in position by bushing I9 threaded into the lower end of the body. 'I'he'valve proper comprises an 'annularly tapered portion 80 normally positioned opposite the inlet and outlet ports 8| and 82, and having relatively slight angularity, the illustrated taperbeing somewhat exaggerated for clarity of illustration. -As will be apparent, opening movement of the valve 43 closes the slide valve 80 to restrict the flow of water through line 6| to the regulator tube,

while closing movement of valve 43 increases'the water supply to the tube.

82 the water may be discharged through pipe 85' and passed to the boiler through a line 86 connecting therewith, or the water may be discharged to a sump or the like through line 81..

In accordance with the second variational form shown in Fig. 5,.the wateris discharged from pipe 51 into a tube or nozzle 58 extending through the casting I6 into the tube I5. 'The nozzle extends through a packing gland 88 which prevents leakage of steam from casting I6 along the nozzle. As illustrated, the nozzle may be provided with apertures 89 along its length so that the water discharged from the nozzle through the apertures may be directed against the sides and top, as well as the bottom of the regulator tube; 1

Considering now the operation of the regulator, it will be understood that preferably, valve 66 will permit a continuous flow of cooling water through pipe 51 to thecontroller tube I5. This flow of cooling water is of course extremely small in 7 order for example of to 1 pints, more or comparison to the feed water flow, being in the less, per minute. During a sudden rise in the boiler water level, the accompanying surge in tube I 5 tends'to cool the tube and to cause its outer end to deflect downward to close the iced the collection of sludge-and renders cleaningof the tube'unnecessary;

water valve 43. ,Closing movement of, the valve, however,- .opens valve lll tosincreasethe flow of :coolinggwaterto the tube 4 l 5;;causing the waterin longitudinal expansion and contraction rof said 7 tube for supplying liquid to said chamber, and

the tubejto be;chang'ed at morerapidr'ate, and

thus preventing-thetube from becom ng eXcessively heated tothe extent of destroying itsgsensitivity As the ,boiler .water, levellowers, the

resultant; heating of tube 15, opens the feed valve 635' and progressively ,closes*valve fill, the two valves thus working together' and in' compensating relationship;v Similarly, when the'water level drops; and a greater lengthof the controller means for controllably applyingcooling fiuid to the upper, portion of, said tube above the liquid level therein to reduce thenormal rate of variation in length of the tube resulting from sudden liquid leVeLchanges in-said chamber.

4,, Apparatus for controlling the level of heated liquid contained in a chamber having-a vapor space above the liquid level therein, comprising an inclined tube,means' connecting the tube with r the liquidand vapor spaces in'said chamber so tubeis exposed to the stream, resultant exp'ansion, oi the tube opens'thei feed valve and movesvalve 1!! in a closing direction torestrict the ,stream of 'cooling fluid. Consequently the lowenthe water, runs downthe tube i5, the greater the heating eflect is had by-diminishing thegstreain of cooling-water. efiects thus make it virtually impossible for, the boiler water to reacha low level if the feed pump is operating-and has an available supply;

'The maintenanceof constant flow of Water through the controltube eliminates .a principal objection to the usual thermostatic tube, in that when there is a. change inwatenlev'el. Also, constant flowofwater through the-tube-prevents 'Iclaim: it 7 f 1-. Apparatus forcontrolling the level of heated liquid contained inia chamber having a vapor spaceabove the llquid level therein, comprising an inclined tube-means connecting the tube with These cumulative.

frequent thati liquid stands in the tube intermediate its ends and surgestherein in accordance with liquid level changes in thechamber, means operated by longitudinal expansion and contraction of said tube 'for supplying liquid to said chamber, and means for controllably cooling the 'upper portion of saidtube'bya lower temperature liquid introduced into the tube. 7

' 5. Apparatus for controlling the level of heated liquidconta-ined in a chamber having a vapor space abovethe liquid level therein, comprising an inclined tube,,me ans connecting the tube with thejtubej now is stabilized in itsaction, and is made less sensitive to weather conditions by keeping; its: temperature more uniform except the liquid-and vapor spaces in said chamber so that liquid stands the tube intermediate its ends and surges therein in accordance with liquid level changes in the chamber, means operated by longitudinal expansion and contraction of said tube for supplying liquid to said chamber, and means for variably cooling the upper portion of said tube by continuously applying thereto a lower temperature liquid flowing at a rate varying in accordance with liquid level changes in said the liquid and vapor spaces in said chamber so that liquid standsrin the; tube intermediate its ends and surges therein in accordance with liquid level'changes in 'thec'hamber; means operated'by longitudinalexpansionaand contraction of said" tube for supplying liquid to said chamber, and means for passing liquid that is considerably cooler thanthe liquid in said chamber, in contactwithathe upperv portion of saidtube and intov the chamber-containedjliquid, to controllably reduce-I'the normal rateiof'va'riation inthe length of said tube'resultingfromliquid levelichanges I in saidchamber; 1 V 7 2. Apparatus for controlling the level of heated liquid contained in a chamber having a vapor 1' space above the liquid level therein, comprising an inclined tube, means connecting the tube with the liquid and vapor spaces in said chamberso that liquid stands in'the tube intermediate its.

endsand surges therein in'accordance with liquid levelchanges in the chamberfmean's" operated.

longitudinal expansion [and contraction of said tube ifor'sup'plyingliquid to'said chamber,' and means for continuously passing a cooling fluid along and in contact'fwith the upper portion of saidtube to c'oolthe tube and reduce itsnormal rate of variation in lengthresulting from liquid level changes in 'saidchamber, said coolingfluid flowing from theztube into the liquidrin said chamben,

space-above the liquid'level therein, comprising an inclined tube, means connecting the, tubewith the liquid and vapor spaces in said;chamber so that liquid. stands in the tube intermediatej its ends and surges thereinin accordance with liquid level changesin the chamber, means operated; by

chamber and passing into the water in said chamber."

means for cooling the upper portion of said tube by a lower temperature liquid discharged into the tube, and valve meansrfor controlling such discharge' of the liquid into the tubal '7. Apparatus for controlling'the level of heated 'liquid contained in a chamber having a vapor space above the'liquidlevel therein, comprising aninclined tube, means connecting the tube with theliquid and vapor spaces in said chamber so that liquid stands in the tube intermediate its 'endsand'surgesthereinin accordance with liquid level chan es in the chamber, a feed liquid supply line connected to said chamber; a valvein said lineoperated by longitudinal expansion and contraction of said tube, means for continuously applying cooling fluid to the upper portion of said 3. Apparatus for controlling the level r heated liquid contained in a chamber havingavapor;

tube, and means operated by said valve for controlling such application offcoolingfiuid to the tube. 3 l,

8. Apparatus for controlling-the level of heated liquid contained in a' chamber having a vapor space above the liquid level therein, comprising an inclined tube, means connecting the tube with the liquid andjvapor' spaces in said chamber so that liquid standsin the'tube intermediate its ends and surges therein in accordance-with liquid level changes inthe chamber, a feed liquid supply line connected to said chamber, a valve in said line operated bylongitudinal expansion andconmediate its ends and surges therein in accordance traction of said tube, means for introducing cooling fluid into the upper interior of said tube above the liquid level therein, and means operated by said valve for Controlling such introduction of fluid to the tube. I

9. Apparatus for controlling the level of heated liquid contained in a chamber having a vapor space above the liquid level therein, comprising an inclined tube, means connecting the tube with the liquid and vapor spaces in said chamber so that liquid stands in the tube intermediate its ends and surges therein in accordance with liquid level changes in the chamber, a feed liquid supply line connected to said chamber, a valve in said line operated by longitudinal expansion and contraction of said tube, means for delivering cooling liquid from the supply line at the inlet side of said valve to said tube, and means operated by said valve for controlling the delivery of said cooling liquid to the tube. V I

10. Apparatus for controlling the level of heated liquid contained in a chamber having a vapor space above the liquid level therein, comprising an inclined tube, means connecting the tube with the liquid and. vapor spaces in said chamber so that liquid stands in the tube intermediate its ends and surges therein in accord ance with liquid level changes in the chamber, a

feed liquid supply line connected to said chamber,

a valve in said line operated by longitudinal ex-' pansion and contraction of said tube, means for applying cooling fiuidto the upper portion of said tube so that the cooling fluid flows into the liquid in said chamber, and a valve connected tothe first mentioned valve and controlling such application of cooling fluid to the tube.

11. Apparatus for controlling the level of heated liquid contained in a chamber having a vapor space above the liquid level therein, comprising an inclined tube, means connecting the tube with the liquid and vapor spaces in said chamber so that liquid stands in the tube intermediate its ends and surges therein in accordance with liquid level changes in the chamber, a feed liquid supply line connected to said chamber, a valve in said line operated by longitudinal expanwith liquid level changes in the chamber, means operated by longitudinal expansion and contraction of said tube for supplying liquid to said ,chamber, means for continuously discharging cooling liquid into the upper portion of said tube, and means for controllably varying the rate of such discharge in accordance with changes in the liquid level in said chamber. 7

13. Apparatus for controlling the level of heated liquid contained in a chamber having a vapor space above the liquid level therein, comprising an inclined tube, means connecting the tube with the liquid and vapor spaces in said chamber so that liquid stands in the tube intermediate its ends and surges therein in accordance with liquid level changes in the chamber, a feed liquid supply line connected to said chamber, a valve-in said line operatedby longitudinal 1 expansion and contraction of said tube, a pipe for delivering cooling liquid from the supply line at the inlet side of said valve into the upper. end of said 'tube, and a control valve connected to the first mentioned valve and controlling such delivery of cooling liquid to the tube, said control valve normally passing a stream of the cooling liquid and operating to increase that-stream when the liquid level in said chamber rises, and to decrease said stream when said liquid level falls.

14. Apparatus for controlling the level of heated liquid contained in a chamber having a vapor space above the liquid level therein, comprising an inclined tube, means connecting the tube with the liquid and vapor spaces in said chamber so that liquid stands in the tube intermediate its ends and surges therein in accordance sion and contraction of said tube, a stem for said withliquid level changes in the chamber, means operated by longitudinal expansion and contraction of said tube for supplying liquid to said chamber and means independent of said connecting means for applying cooling liquid to the upper exterior portion of said'tube above the normal liquid level therein and for conducting the cooling fluid into the liquid in said chamber.

15. Apparatus forcontrolling the level of heated liquid contained in a chamber having a vapor space above the liquid level therein, comprising an inclined tube, means connecting the tube with the liquid and vapor spaces in said chamber so that liquid stands inthe tube intermediate its ends and surges thereinin accordance with liquid level changes in the chamber, means operated by longitudinal expansion and contraction of said tube for supplying liquid to said chamber, and means independent of said connecting means for introducing coolingliquid into said tube above the normal liquid level therein.

JULIAN A. CAMPBELL, 

